Observing and engaging in purposeful actions with objects influences estimates of their size

A ladle was recalled as being taller by participants who observed tedious removal of sand from it with a small teaspoon than by those who observed removal with a larger spoon. A second experiment showed that the number of darts thrown in order to hit a target correlated negatively with memory estimates of the size of the target, a finding replicated in a third experiment with size estimates made while the target was visible. The first two experiments suggest that the way an object is used can influence memory of its size. The third experiment supports the hypothesis that in vivo size estimation of familiar objects may employ a mechanism that derives size from memory and that size memory can be distorted by the way an object was used.     

Self-concept and psychosocial adjustment in adolescence

This study analyses the relationship between a multidimensional measure of self-concept, Self-concept Form-5 Questionnaire (AF5), and a broad set of adolescents' psychosocial adjustment indicators. From the responses of 1,281 participants (53.7% females) aged 12 to 17 years ( M = 14.98 years, SD = 1.74 years), results indicated that higher self-concept scores corresponded to better psychological adjustment, good personal skills and fewer behavioral problems. Although a positive relationship between social self-concept and drug use was found, this significant relationship disappeared once the adolescent's age and sex was controlled for. These results support the idea that the self-concept is a basic theoretical construct closely related to the psychosocial adjustment in adolescence. Also this study helps explain some contradictory results reported in the literature (i.e., a positive relationship between social self-concept and drug use), by showing how the statistical control of a third variable effect (i.e., age) avoids reaching conclusions based on spurious relationships.     

Depiction of an object's size in drawings subsequent to interaction with the object

Subsequent representation of the size of the object in a visuomotor activity was evaluated after an object was used differentially in two ways. 25 female and 17 male students volunteered from general psychology courses and were randomly assigned to a condition in which participants used a small teaspoon to remove sand from a ladle or simply moved the ladle. Those who removed sand drew a representation of a ladle that was taller than did participants who moved the ladle. It appears, given the time-consuming activity of removing sand, the ladle appeared to contain more sand and seemed larger. Findings suggest that the way an object was used may distort memory of its size and that subsequent representation of the size in a visuomotor task can be influenced by that memory.     

Inattentional blindness for negative relationships in human causal learning

The present study focuses on the effect of selective attention on causal learning. Three effects of the level of attention to predictive symptoms in positive and negative contingency learning tasks are reported. First, participants accurately detected a positive relationship between an incidental cue and a contingent outcome, although judgements were slightly lower than those for the attended cue. Second, participants were unable to detect negative relationships between incidental cues and outcomes, which suggests a major role of selective attention in this type of learning. Third, participants retrieved the frequency of each trial type more accurately in the attended conditions than in the incidental conditions. These findings show how attention guides and constrains human causal learning and reveal an inattentional blindness effect for negative contingency learning.     

Evaluation of three sensitivity measures in magnitude estimation tasks

Taking into account the studies about the measure of sensitivity in magnitude estimation tasks, we analyze the three most common measures used in this topic: Pearson's product-moment correlation between the logarithm of the stimulus and the logarithm of the response (R), the exponent of Stevens' power function (K), and the measure "M" proposed by Garriga-Trillo. Using a sample of participants greater than usual in psychophysical studies (180 participants), we designed an experiment with two sets of stimuli with different stimulus ranges. In each of these sets, we used two kinds of stimuli (line segments and squares). Our conclusions were: (1) we rejected the use of K as a sensitivity measure because the results provided by this index were the opposite of those expected when we compared the two stimulus ranges. (2) We also rejected the use of M because this measure is a linear transformation of Kendall's coefficient of concordance. (3) Lastly, we suggest the mathematical transformation proposed by Fisher to achieve a normal distribution, and recommend this transformation as the best sensitivity measure.     

Multiple victimization of Spanish adolescents: a multilevel analysis

Multiple victimization in adolescence is an issue that has received little research attention. Furthermore, adolescents are particularly vulnerable to victimization in different contexts. The aim of this study is to analyze correlates of multiple victimization in three contexts (home, school, and street). The following forms of victimization were considered: stealing, hitting, insulting, threatening, blackmailing, and weapon intimidation. Multiple victimization correlates explored were: sex, age, public/private school, socioeconomic status, quality of family relationships, and antisocial behavior. A probabilistic sample of 1,908 adolescents (ages 13 to 18) was used. Multilevel analyses were conducted to separate correlates at the individual level from those operating at the contextual level. Results show that gender, quality of family relationships, and deviant behavior were related to multiple victimization in adolescence.